2.1.1. Pseudopyronines A and B
While a number of methodologies have been reported for
the preparation of 4-hydroxy-2-pyrones, the carbonyldiimidazole-mediated
condensation of b-keto carboxylic acids22 was
particularly attractive for the synthesis of the pseudopyronines
as it could also lead to the preparation of a number of related
compounds for structureeactivity studies